Electric fence



June 15, 1948. w. F. FAGEN ELECTRIC FENCE Filed NOV. l5, 1943 PatenteclJune 15, 194i;

ELECTRIC. FENCE William F. Fagen, Chicago,- Ill.,-vv assigner-WoStewart-Warnerl Corporation,- Chicago, HIll.,.a corporation of VirginiaApplication November 15, 1943,.Serial No. :510,310

(Giese-10) 3 Claims.

The present invention relates to electric fences,

and particularly to apparatus for` automatically energizing or charginga fence to'produce'a shock Lwhen an animal contacts the' fence.

An `object of the present invention is to prvide .a new and improvedelectric fence `charging i:

apparatus wherein a voltage is applied tothe fence for a predeterminedinterval to produce a .shock when an animal contacts pthe fence.

A further object of the present invention `is to providea new andimproved apparatus-of the characterv specified wherein a Acontrolvoltage,

f preferably of low value, is'normally appliedto the fence and a changein voltage `occurring lwhen an animal conta-cts the fence is utilized toeffect the operation of a relay to connect a source Vof provide a newand improved apparatusof the v character specified wherein the voltageYapplied to the fence is an alternating current'voltagefand .maximumcurrent flow through the fence is limited to a sale value.

Other objects and advantages of thepresent invention will becomeapparent from the ensuingdescription, in the course of which vreferenceis had. tothe accompanying drawing, thel single figure of `which vis adiagrammatic illustration of one-embodiment of the invention.

The fence charging apparatus is indicated gen- Y -frallynby referencecharacter I0.

It is lpreferably adapted to be connected to alternating current voltagesource through a plug connector I2 anda power switch I4. It has apair ofoutput terminals I 6 and I8 connected to the fence which, intheillustrated embodiment, comprises a Ybare conductive wire supported by aseries of -fence 4posts 22 (only one of which has been shown) havinginsulators 24 actually supporting the wire.

The posts are placed inthe earth in-conven,

tionalmanner.' Terminal I6 is connected to'wire 2'0Land terminal I8 isconnected to `earth'through a conductor 26.` It should beunderstoodfhoweven-that in some installations it is preferable touse twoor more fence wires, onecorrespond-w Afromleaving or entering thepremises.-

2 The fence-'charger-Izincludes-means providing a `'control -voltage`which is normally applied -to the fence, and means providinganother-voltage adaptedto beA appliedv tothe fence toprovide a shockingimpulse -whenanv animal. comes into contact with the fence. The controlvoltage, whichispreferably a relatively lowdirect current voltage(say-of about 300 volts) ris provided by a ful1=wave rectifier-includinga tube 28, the yplates lof which are connected to the terminals of asecondary winding `of a transformer 32, the primary winding 34 of whichis connected to the powerswich i4 through a pair of fuses 36. The tube28- includes -alsoa filament supplied with current `from-another-secondary winding Elfi.A The filamentl ofA the rectifier tube, formingthe positive-terminal of the control voltage, is connected throughV ailterr--resistorito a conductor 42 leading-to the output terminal I6,which itvmay `be remembered isconnected-.to the lfence Wire 20: IThe-negative side lof the control voltage is connected to the outputterminal I8 and. to ground -througha conductor 441connectedto theVcentertap-of transformer4 winding 30 anda conwtrolresstor AGI 'Aiilte'rcondenser 48 is connected across conductors 42 and 44'and serves,with resistor 40,htovsmooth the direct current acontrol voltage `appliedto thel fence.

Whenan animalcontacts the 'fence there is yan increase in 'current flow4across -the control resistor =46= anda resulting .change in voltage`drop thereacross. This change in voltage is;utilized toeffecttheconnectionof the shockfprovding voltage :source across .the fence'.for fa predetermined-length of. time. Theevoltage thus applied tothe-Eence is *suppliedv bya secondary Winding-50,fone-terminal of ywhich is.connected through conductor 42 to the fence Wire 2U and lthel otherterminal of. which is Aadapted to be connected togroun'd. terminal I8byv ,a switch 52 YformingY part ofv a relay-including a winding 54adapted to be energized in-.a manner to bedescribed shortly." Whentherswitch v52 is closed, a circuit lis' completed acrossconductors 56and 58,!therebytoefect.the connection of secondary windingfdirectlyacross the..,fence wire and ground. f The :winding 50 .may be`constructed to produce an opencircuit .voltage of the order of severalthousand volts. Y

Currentflimiting means arerprovided innorder tol'limit the current..applied to the fence'to a .safe value.2v In' the .instant embodimentther cur- Yrent limitingv :means includes a loose magnetic coupling ofthe vsecondarycwinding v5t tothe `pri- Lkmary winding f341'of. .thetransformer. l This construction provides what is essentially a constantcurrent transformer, i. e., the secondary winding EU is the secondaryWinding of a constant current transformer. The -coupling is so adjustedas to limit the maximum current to the desired value.

The relay 54 is energized in response to contact between the animal andthe fence by means responsive to a change in voltage across the controlresistor 45. This means includes preferably a cold cathode gas dischargetube 60 operated just below its breakdown point. Voltage is supplied tothe tube from the rectier tube through resistors t2 and S4, and therelay, Winding. When the flow of current through resistor 46 increases,the ground end of resistor 46 becomes more positive and this positivepotential is applied to the positive terminal of the tube through aresistor 66 and a condenser E8, the purpose of which is to prevent thebreakdown of the tube in response to slow changes in current flow, suchas might be caused by rainfall or the like.

,change in voltage across resistor 45. The inductance and resistor 64aid in preventing the control impulse from being applied elsewhere thanacross the tube. Resistor 64 serves primarily to govern the time thatrelay 54 is maintained in its operated condition. y

Once therelay is energized, it remains energized for arti-me that ispredetermined by the values of the previously referred to resistor 6,2and a condenser lll connected between conductor 44 and the junction ofresistors 62 and 64. The time interval during which the relay isenergized and the shocking voltage is applied to the fence is preferablyadjusted to conform to codes governing the construction and operation ofYapparatus of this character. Y u,

Reviewing briefly the operation of the apparatus, itis assumed firstthat the switch I4 has been yclosedlto place they apparatus inoperation. Un-

der normal conditions, i. e., when there is no contact between the fenceand an animal, the relay 54 is deenergized, switch 52 Ais opened so thatthe only voltage applied to the fence is the relatively Vlow directcurrent control voltage, and the voltage across tube 6U is just belowthe breakdown voltage of the tube. v

vWhen an animalcomes .into contact with the fence, the flow of currentthrough resistorA 46 increases to increase the voltage drop ,thereacrossThe change in voltage drop across resistor-46 is sufciently rapid sothat a portion of it is applied across the tube through the condenser 68and results in the breakdown of tube 60, which, it ymay be remembered,is operated just below its breakdown point. When the tube breaks downthe condenser 'l' discharges through the resistor 64, which is a currentlimiting resistor, the relay winding, and tube 60. The ,relay` remainsenergized for a length ofv time determined by the val-v -ues of thecondenser 10, resistor 62 through which the condenser is charged,resistor 64 and the electrical constants of relay 54. Upon energizationof the relay the switch 52 is closed,and upon ldeenergization of therelay the switch is opened.

Whenthe relay 54 is energized the voltage appearing across the secondarywinding 50 is applied across the fence to provide the desired shockingimpulse.V Once the relay has been operated, i. e., closed and opened,it'cannotbe energized for a definite time interval controlled largely byresistor 62 and condenser l0, and furthermore, no succeeding impulseoccurs unless there is a further change in current iiow through resistor46, as by a second animal coming into contact with the fence or the rstanimal again coming into contact with the fence after having disengageditself therefrom.

While ,the condenser 48 is connected to the fence, it does not produceany substantial shocking effect when the fence is contacted by an animalbecause of the magnitude of control resistor 46, which may have a valueof about .1 megohm.

While a preferred embodiment of the invention has been described indetail, many modications ,may be made without departing from the spiritof the invention, and I do not wish to lbe limited to the details ofconstruction set forth, but desire to avail myself of all changes withinthe scope ofthe appended claims.

Having thus described rny invention, what I claimas new and desire tosecure by `Letters'Patent'of the United States is:

1. Apparatus for energizing afence comprising a conductive wire adaptedto complete a circuit through the body of an animal contacting the wire,including in combination, a sourceof voltage normally disconnected fromthe fence circuit, means including an electron tube and a re-Q layhaving a winding in series with said tube controlled in response tocontact between an animal and said wire foi-,connecting said voltagesource to the fence circuit, and meansincluding a condenser adapted todischarge through said tube and relay winding for maintaining saidconnection for a predetermined length of time.

2. Apparatus for energizing a fence comprising a conductive wire adaptedto complete a circuit through the body of an animal contacting the'wire,including in combination, a high voltage source of voltage normallydisconnected from the fence circuit, means supplying said fence with alow control voltage, means' including a low voltage vsource of voltage,an electron tube associated with said second low voltagesource and arelay having a winding inv series with said tube controlled in responseto a change in current ow through the fence wire occurring upon`'contact between an animal and said wire' for connecting said highvoltage 'source to :the fence circuit, and means including a condenseradapted to discharge through said tube 'and' relay winding formaintaining said connection` for ya predetermined length of time. y Y uY y 3. Apparatus for energizing a fence comprising a conductive wireadapted to` complete a circuit through the body of an animalcontactingthe wire, including in com'binatior1,`al high supplying said `fence witha low control voltage,

`means including a low voltage source of voltage,

a cold cathode gas tube 'connected to saidlow voltage source andnormally suppliedjwith a voltage slightly below its breakdown voltageand a relay having a winding in series with said tube controlled inresponse to'l a change in Acurrent iiow through the fence wireoccurringupon contact between an animal and said wire for connecting 4said highvoltage source to `the fence circuit, saidV last mentionedV meansincluding means for effecting breakdown of said tube, and meansincluding a condenser in circuit Vwithvsaid relay and tube and normallychargedby said' low voltage sourceuand adaptedto discharge through saidtube and relay winding up'on breakdown of Name Date Pfanstiehl July 15,1941 Agnew et al Apr. 13, 1943 Roach Mair 11, 1943 Agnew NOV. 2, 1943Klumb Mar. 7, 1944 FOREIGN PATENTS Country Date Australia Nov. 8, 1939OTHER REFERENCES Agricultural Engineering, vol. 20, No. 1, January 1939,page '7, paragraphs 1 and 2.

Certificate of Correction Patent No. 2,443,232. June 15, 194s.

WILLIAM F. FAGEN It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows: Column 1, line 24, forsale read safe; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Office.

Signed and sealed this 31st day of August, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,443,232. June 15, 1948.

WILLIAM F. FAGEN It is hereby certied that error appears in the printedspecification of the above numbered patent requiring correction esfollows: Column 1, line 24, forsale read safe; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Oflice.

Signed and sealed this 31st day of August, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

